Negative side effects can be associated with systemic exposure to oral drugs that are absorbed into the blood stream through the intestine, and circulate throughout the body. For some drugs, in particular those that are indicated for gastrointestinal symptoms or for those that exert their effects through the gastrointestinal system, it is desirable to keep the drugs within gastrointestinal tissues, such as intestinal cells, rather than circulating through the body. Accordingly, there is a need in the art for methods of specifically targeting drugs to intestinal cells.